What it means
The exhaust camshaft actuator park-lock circuit on bank 1 is below the expected electrical threshold. This indicates a low circuit condition, not necessarily a specific short or internal driver failure.
At a glance
- Usually lights the check-engine light
How it works
The exhaust camshaft actuator park-lock circuit on bank 1 operates the solenoid that holds that exhaust phaser in its parked position when required. P25D1 sets when the control module detects a circuit level below its expected threshold; this low reading can come from a grounded wire, driver fault, or poor connection.
Common causes
Most likely first.
- Control wire shorted to ground
- ECU low-side driver internally shorted
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Power loss especially in mid-rpm range
- Possible rough idle or stalling
- Increased fuel consumption
How to diagnose it
- Save freeze-frame data and related actuator codes, noting when the bank 1 exhaust circuit went low.
- Inspect the bank 1 exhaust park-lock connector and harness for corrosion, damaged pins, chafing, or a wire touching ground.
- Check terminal fit and condition, since corrosion or poor contact can affect the circuit reading.
- Measure the circuit at the solenoid and control-module connectors under the manufacturer's test conditions to locate where the low condition appears.
- Isolate the solenoid and harness as directed, then test for a short to ground and compare solenoid and driver behavior with manufacturer specifications.
Common fixes
- Clean, secure, or repair corroded terminals at the bank 1 exhaust park-lock connector.
- Repair a bank 1 exhaust control wire shorted to ground.
- Replace the park-lock solenoid if it fails the manufacturer's electrical test.
- Repair the control-module driver only after the solenoid and wiring pass testing.
Can I keep driving?
If the engine runs normally, limit driving to a cautious trip for diagnosis and avoid heavy acceleration. Stop in a safe place if rough running, stalling, or power loss occurs.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.